I'm wondering how you were able to create an instance with these values. Could you also provide information of the base image qemu-img info /var/lib/nova/instances/_base/c4cb69e2629d118506c456884778e0ffb68d3bbf

How much disk space does the instance see? Please show output of fdisk -l from inside of your instance. Please use the respective format buttons (code tags) when commenting or editing your question. It's recommended to edit your question with additional information rather than commenting.